So I was bored today and was rummaging around the engine compartment, decided to check the air filter (nothing is seemingly wrong with the car, it's doing rather well). But I pulled the air filter and other than it being somewhat dirty, the date code stamped on it is 08/10/02, original BMW part number and everything. WTF am I missing? It's been in for all of its service at Hendrick, and they never bothered to change the filter? Is this the date is was produced or is this the date the design was last revised?